spare front diff
spare rear diff
tie rods
half shafts
an H2 to pull you back to the trailhead.
The only we bring other than a ton of tools, are two complete tie rods and 1 half shaft. We have yet to break these on ours, but it's a matter of time before we or someone else in the group may need one.
It's funny, I always carry tierods in the H2 also (for the H2). I have never broke one, but have handed two over to others in our group over the last three years.